Gas carburetor



Filed May 22, 1951 F. E. PILLING ET AL GAS CARBURETOR 2 Sheets-Sheet lINVENTORS FRANK E. PILL/N6 BY E/CHA/ED BAVERSTOCK ATTORNEY W W56 (F. E.PJILLBNG ET AL GAS CARBURETOR 2 Sheets-Sheet 2 Filed May 22, 1951INVENTORS FRANK E. FILLING BY RICHARD BAVEQSTOQX,

ATTORNEY United States Patent GAS CARBURETOR Frank E. Filling andRichard Baverstock, Lynwood, Calif. Application May 22, 1951, Serial No.227,616

4 Claims. (Cl. 48--184) This invention relates to carburetion forinternal combustion engine and particularly to an improved carburetionsystem for liquified gases such as for butane or liquid propane.

It is an object of this invention to provide a liquified gas carburetorhaving improved control of the combustion mixture of gas and air.

It is another object of this invention to provide a liquified gascarburetor in which the fuel gas is metered into the combustion airstream downstream from the throttle valve.

it is another object of this invention to providein a liquified gascarburetor means for controlling accurately the richness of the fuelgas-air mixture for all flow rates of the carburetor.

it is another object of this invention to provide a liquified gascarburetor having predeterminable gas to air mixture ratios for allthrottle openings.

it is another object of this invention to provide a liquified gascarburetor in which the richness of the fuel gas-air mixture iscontrolled in response to the rate of air flow through the carburetor.

-t is another object of this invention to provide a liquified gagcarburetor in which the richness of the fuel gas-air mixture is optimumwhen substantial power is required of the engine and somewhat richer orleaner when the engine is idling.

It is another object of this invention to provide an improved meteringvalve for a vaporized liquified petroleum gas carburetor.

Other objects of the invention will become apparent from the followingdescription taken in connection with the accompanying drawings in which:

Figure 1 i an elevational view of the invention installed on an internalcombustion engine,

Figure 2 is a vertical sectional view of the invention,

Figure 3 is a plan view of the device taken at 3-3 in Figure 2, V

Figure 4 is a fragmentary section taken at 4-4 in Figure 2,

Figure 5 is a side elevation view at 55 in Figure 1,

Figure 6 is a sectional view taken at 6-6 in Figure 2, and

Figure 7 is a fragmentary view of the invention taken at 7-7 in Figure2.

Referring now to Figure 1, carburetor body 1 is attached to manifold 2of internal combustion engine 3. Vaporized liquified petroleum gas isintroduced into carburetor 1 by means of fuel conduit 4 through pressureregulated valve 5 and metering valve 6. Metering valve 6 is actuated bylever 7 attached by drag link 8 tolever 9 connected to shaft 10 of thecarburetor throttle valve. Pressure regulated valve 5 is connected tocarburetor body 1 by vacuum line 11.

Referring now to the remaining figures and particularly to Figure 2,butterfly valve element. 12 attached to shaft 10 controls flow of airthrough body section 1 ofthe carpartly in section taken 2,763,538Patented Sept. 18, 1956 buretor. Shaft 10 is connected by drag link 8 tolever 7 which in turn is connected to valve element 13 of rotary valve6, so that rotary valve 6 opens when butterfly valve element 12 opensand at the same rate valve 6 is formed by drilling coaxial passages 31and 32 in body 6, leaving web 30 through the center of which is disposedrotary valve element 13. Vaporized liquified petroleum gas flows throughvalve 6 and into annular chamber 14'separated from the interior of body1 by spray ring 15 of venturi form having evenly spaced holes 16 on thedownstream side thereof. Upwardly from butterfly valve element 12 andpositioned athwart carburetor body 1 is cylindrical tube 17 having aplurality of evenly spaced holes 18on one side thereof. Cylindrical tube17 is rotatable in body 1 by means of slot 19 and communicates withvacuum line 11 which is also connected to pressure regulator valve 5shown in detail in Figure 5.

Referring now to Figure 5, vacuum from line 11 actuates diaphragm 20which in turn actuates inlet valve 21 through levers 22 and 23restrained by compression spring 24. The lower side of diaphragm 20 issubject to vacuum from fuel conduit 4 so that movement of the diaphragmand hence flow of fuel gas through the pressure regulator is governed bythe difference between the vacuum due to tube 17 and the vacuumcommunicated through conduit 4.

In operation, the device functions as follows: Body 1 is typicallyattached to the engine intake manifold so that air is drawn through body1 in the downward direction in Figure 2. Body 1 coud however, be mountedin any other convenient position. Motion of the indrawn air throughventuri insert 15 causes fuel gas to be drawn into body 1 in aproportion to the air drawn determined by the opening of valve 6 andbutterfly valve 12. As shown in Figure 6, valve element 13 is shapedlike the intersection of a right circular cylinder with two nearlytangent half-cylinders. It may readily be appreciated that the shape. ofvalve element 13 may be varied somewhat to suit varied operationalconditions. The natural result of this valve configuration is that asvalve 6 is opened in unison with butterfly valve 12, the increased flowof air through the valve is matched by a proportionate increase in flowof fuel gas through valve 6. By means of stop 25 shown in Figure 1, bothbutterfly valve 12 and rotary valve6 are held slightly open when theengine is idling and drag link 8 is adjustable to the proper length sothat the proper proportion of air to fuel gas is supplied to the intakemanifold for economical idling.

Although the increase of flow of fuel gas through rotary valve 6 isproportional to the increase of flow of air through butterfly valve 12as these valves are opened, machining tolerances, atmospheric conditionsas affected: by altitude, temperature, and humidity and the condition ofthe engine as determined by Wear, age, and type, may cause the mixtureratio of fuel. gas to air to be other than optimum at full throttle. Toallow very fine and exact adjustment of the fuel gas to air ratio atfull. throttle, tube 17, line 11, diaphragm 20, and inlet valve 21 areprovided. The combination of these elements with the other parts of thecarburetor permit a precise adjustment of richness of the fuel gas toair ratio thus allowing predetermined power at full throttle. As will bepresently disclosed, this richness adjustment is of no effect when theengine is idling but is highly eflectit e when the engine is operatingat or near full throttle.

Referring now to Figures 1, 2, and 5, when air is beirtg drawn throughthe carburetor at a relatively high rate, as when the throttle is openor nearly open, the flow of air past holes 13 in tube 17 causes apartial vacuum therein, which vacuum may be adjusted in amount byrotation of tube 17. If tube 17 is in the position shown-in Figure 2,actually no measurable vacuum is angles to direction of the air stream.Now this vacuum' is communicated to the upper side of diaphragm 20 whichin turn controls the flow of fuel gas to the carburetor by means ofvalve 21. The lower side of diaphragm 20 is subject to the vacuum infuel conduit 4 connected to body 1 through venturi insert 15. Thenatural effect of vacuum in conduit 4 is to pull diaphragm 20 inwardallowing more fuel gas to enter through valve 21. However, to the extentthat line 11 furnishes vacuum to the opposite side of diaphragm 20 theopening of valve 21 is retarded or prevented. Therefore at full ornearly full throttle, the angular position of holes 18 in tube 17, andhence the vacuum on the upper side of diaphragm 20, may be accuratelyadjusted until analysis of the exhaust gases indicates the desiredmixture ratio has been attained. In other words, the screw driveradjustments of the angular position of tube 17, as shown in Figure 7, isreally a trimming richness adjustment at full or nearly full throttle.The effect of this adjustment is greatest at full throttle but is alsopresent at lesser throttle openings.

Although the invention has been described and illustrated in detail, itis to be clearly understood that the same is by way of illustration andexample only and is not to be taken by way of limitation, the spirit andscope of the invention being limited only by the terms of the appendedclaims.

We claim:

1. Carburetion apparatus comprising a hollow cylinder reduced incross-section at one end to form a constriction and adapted to beattached at that end to the intake manifold of an internal combustionengine, manifold means surrounding said constriction for introducing agas into said cylinder immediately adjacent to said constriction andbetween said constriction and said intake manifold, a butterfly valvefor controlling flow of air through said hollow cylinder, a gas valvefor controlling flow of said gas into said cylinder, means for actuatingsaid two valves together, a third valve for controlling flow of said gasbefore it enters said gas valve, a hollow tube placed diametrally nearthe non-constricted end of said hollow cylinder having a plurality ofdrilled holes on one side and rotatable in said hollow cylinder, andpressure regulator means responsive to the difference between thepressure in said hollow tube and the pressure in said manifold means forcontrolling flow of said gas through said third valve whereby rotationof said hollow tube is effective in achieving fine adjustment of therichness of the mixture of said gas and air.

2. In a gas carburetor having an air metering valve and a substantiallycylindrical body section attached at its lower end to the intakemanifold of an internal combustion engine flow of air through which iscontrolled by said air metering valve, means for controlling therichness of the gas-air mixture furnished to said intake manifoldcomprising a hollow manifold shaped to fit within said body sectionbelow said air metering valve and having inner surfaces adapted to forma venturi shape within said body section, the lower divergent section ofsaid venturi shape being perforated to permit entry of gas from saidmanifold into said body section, a pressure regulator having a diaphragmresponsive to differential pressure on the opposite sides thereof, and avalve operable in response to motion of said diaphragm, a hollowcylindrical tube perforated on one side rotatably placed athwart saidbody section above said air metering valve, a conduit for connectingsaid tube to the space on one side of said diaphragm and conduit meansfor connecting said manifold to the other side of said diaphragm wherebysaid richness may be controlled by rotation of said tube.

3. A liquefied gas carburetor comprising a cylindrical throat sectionadapted to be attached to the intake manifold of an internal combustionengine and defining the flow path of said air entering said intakemanifold, a butterfly valve associated with said throat section so as torestrict the passage of air therethrough, a substantially cylindricalextension of said throat section extending downstream therefrom andhaving a cross-section area less than said throat section, a conduit forsupplying a fuel gas to said reduced diameter section, a valve in saidconduit for controlling the flow of fuel gas in said conduit, mechanicallinkage means for controlling the motion of said butterfly valve insynchronism with the motion of said fuel gas valve, a pressure regulatorfor controlling flow of fuel gas to said fuel gas valve, an adjustablemeans, including a hollow tube, placed athwart said throat section andhaving a plurality of perforations along one side thereof and a conduitconnecting said tube and said pressure regulator for controlling saidpressure regulator in response to flow of air through said throatsection to thereby adjustably control the mixture ratio of fuel gas andair passing through said carburetor throat section.

4. A carburetor comprising a cylindrical case having a venturi throatsection of reduced diameter, a butterfly valve in said cylindrical caseon the upstream side of said throat section, a manifold surrounding saidthroat section and communicating by means of a plurality of evenlyspaced peripheral holes with said throat sections on the opposite sidethereof from said butterfly valve, a hollow tube having a plurality ofevenly spaced peripheral holes along one side thereof placed across saidcylindrical case upstream from said butterfly valve and rotatable insaid casing, a conduit for furnishing combustible gas to said manifold,a valve in said conduit for controlling flow of combustible fuel gasinto said manifold, a mechanical linkage for opening and closing saidgas valve and said butterfly valve together to provide substantiallyconstant fuel gas to air ratio for all valve openings, a closed chamber,a diaphragm placed across said chamber, a conduit for connecting thespace on one side of said diaphragm with said hollow tube, a conduit forconnecting the space on the other side of said diaphragm to the inlet ofsaid gas valve, conduit means for furnishing fuel gas to the side ofsaid diaphragm to which said last named conduit is connected and valvemeans responsive to movement of said diaphragm for allowing flow of gasthrough said last named conduit whereby rotation of said tube causessuflicient variation in the movement of said diaphragm to provideadjustment of the richness of the fuel gas to air mixture at full openposition of said butterfly valve and said gas valve.

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3. A LIQUIFIED GAS CARBURETOR COMPRISING A CYLINDRICAL THROAT SECTIONADAPTED TO BE ATTACHED TO THE INTAKE MANIFOLD OF AN INTERNAL COMBUSTIONENGINE AND DEFINING THE FLOW PATH OF SAID AIR ENTERING SAID INTAKEMANIFOLD, A BUTTERFLY VALVE ASSOCIATED WITH SAID THROAT SECTION SO AS TORESTRICT THE PASSAGE OF AIR THERETHROUGH, A SUBSTANTIALLY CYLINDRICALEXTENSION OF SAID THROAT SECTION EXTENDING DOWNSTREAM THEREFROM ANDHAVING A CROSS-SECTION AREA LESS THAN SAID THROAT SECTION, A CONDUIT FORSUPPLYING A FUEL GAS TO SAID REDUCED DIAMETER SECTION, A VALVE IN SAIDCONDUIT FOR CONTROLLING THE FLOW OF FUEL GAS IN SAID CONDUIT, MECHANICALLINKAGE MEANS FOR CONTROLLING THE MOTION OF